Bugger indeed!

Hope they manage to get on top it soon.

Oct 7, 2020 14:07:25 GMT 12 sub said:

Looks as if I will need to replace the tweeters in the Kef 104/2s, but not yet as have some personal expenses to deal with first.

I noticed this back in late August but forgot to post it then:

www.midwestspeakerrepair.com/shop/home-audio/tweeters/dome/mw-audio-mt-1191-1-inch-dome-tweeter-for-kef-104-2-speaker/

Thanks RdM

Also have these to choose from -

www.madisoundspeakerstore.com/morel-soft-dome-tweeters/morel-mdt29-4-4-ohm-textile-dome-tweeter/

www.wilmslowaudio.co.uk/vifa-dx25tg-59-04-diameter104mm-694-p.asp

From what I have read on line, the Morel one seems to be the one to get.

Hi sub,
Failed tweeters would usually make the spkrs sound dull (not bright) - ie, dead tweeters.
Unless they are distorting, ie. partially damaged somehow.

However, people talk about needing to renew Ferrofluid in these T33 tweeters - see online, I've never looked into this. Axent again, could be the best source of advice here.

In your 'Taking KEF 104/2 apart' restoration thread, did you check the tweeters? DCR Ohms measurement for starters.
Also a listen to them close up when playing (tweeters usually sound tinny & & thin when listened to close up/independently), you may be able to hear something amiss.

Perhaps don't rush into getting new tweets, it seems like there's a can of worms out there when replacing with non-original tweeters.

DarkLantern blog - darklanternforowen.wordpress.com

Owen is exactly right. Before buying new tweeters you'd need to know the crossover frequency for the tweeter, the impedance of the tweeter at that frequency (it won't be 4 or 8!), whether or not the crossover has a zobel circuit to correct any undue rising impedance of the tweeter (and to flatten the output where there is a peak) and the efficiency. The new tweeter must match this in terms of impedance at the crossover frequency, any rising impedance (there will be and it has to be the same as the T33) necessitating the same zobel correction and efficiency. So the first thing to check for is a Stereophile test (JA usually) of the KEF104/2 and look at it's (corrected by a zobel which it will almost certainly have) impedance trace or obtain this information from KEF and check this against e.g. Morel specifications. Better still get someone to test the impedance of your T33 (disconnected) so you can see the impedance without a zobel and then do a matching exercise. If you can't do that, you can calculate the values of a 'new' zobel for your chosen new tweeter from the manufacturer's specs. It is unlikely to be the same as the T33 unless someone has made a recommendation for e.g. a Morel tweeter (damn fine tweeters), having performed these calculations.

Oct 8, 2020 7:34:46 GMT 12 sub said:

Thanks RdM

Also have these to choose from -

www.madisoundspeakerstore.com/morel-soft-dome-tweeters/morel-mdt29-4-4-ohm-textile-dome-tweeter/

www.wilmslowaudio.co.uk/vifa-dx25tg-59-04-diameter104mm-694-p.asp

From what I have read on line, the Morel one seems to be the one to get.

The midwestspeakerrepair ones I linked to appear to be an exact a clone of the original 104/2 original tweeter though. Made in China.

Might be good! How much formerly UK gear is now made in China? Maybe they had the old or original  patterns to work to.

Anyway, it would obviously fit, physically and presumably electrically, without having to adapt the crossover for some newcomer tweeter substitute.

From the little I've read about DIY ferrofluid replacement you need the same viscosity as the originals, and who knows what that was?

(the theory being that it dries out with age and impedes voice coil movement?)

Elsewhere I read that that T33 model was unique to the 104/2 and the only T33 variant to have ferrofluid.

Aug 21, 2020 18:28:22 GMT 12 Citroen said:

Oh, you underestimate the power of a good image!

Do you mean like that Citroen Avatar?

Thanks all for your input. However, both the vifa and morel tweets are reported in several on line posts, as being the right match without modifying xovers.

For example see -

I followed that you tube video when upgrading the xovers - new caps supplied by falcon Acoustics, and kindly installed by our own MikeA. At that time the tweeters seemed to be working ok. Yes, did a check of the tweeters with my multimeter at the time, and they measured to spec. On most music they still seem ok, except for when Emmy Lou Harris’ voice started sounding very screechy and unlistenable. I guess I really should know is her voice being reproduced mostly from the tweeters or midrange?

I won’t be doing anything re the tweeters until next year. Several more important things to do first

Listen like a Pro?:

Many music listeners believe in eliminating sidewall 'first reflections', in order to hear only 'direct' sound from their loudspeakers.

This is a more 'analytical' approach to listening to music.

Professional mixing & mastering engineers do this, avoiding sidewall reflections & spatial effects makes it easier for engineers to hear what's going on sonically.

STEREOPHILE (15 Oct '20) Editor Jim Austin suggests however, that home music listeners perhaps should not do this....

" Among audiophiles, it's practically dogma that sidewall reflections are bad... "

However..."sidewall reflections...can expand the soundstage under appropriate conditions. "

As some Yamaha engineers reported in 1979... "when evaluating the sonic performance of products they were developing, they listened without sidewall reflections. But when listening for pleasure, they listened with reflections. It sounded better. "

" Listening for maximum information retrieval and listening for pleasure are two very different things. " (Jim Austin)


My own experience too, is that some sidewall and/or 'secondary' reflected sound is necessary for me to perceive a wider & more 'spatial' stereo sound 'picture'.

DarkLantern blog - darklanternforowen.wordpress.com